FG of Highly-Caramelized Wort

[jscherff]

Last week I attempted a clone of of North Coast Old Stock:

Stats

• Vol: 5 gallons
• OG: 1.113
• FG: 1.025 (target)
• IBU: 37
• ABV: 12% (target)

Ingredients:

• 22 lbs Maris Otter
• 1 lb Crystal 15L
• 8 oz Special B
• 2 oz Fuggles @ 60 min
• 1.25 oz Fuggles @ 15 min
• 1 oz EKG @ 0 min
• WLP007 Dry English Ale (3 liter starter, cold-crashed and decanted)

Process

• 2 hour mash @ 151°F with 4 gal decoction to achieve 175°F mash-out
• 3 hour boil with separate reduction of 1.25 gallon 1st runnings to 1 pint
• 7 day primary @ controlled 69°F-74°F
• 28 day secondary @ ambient ~65°F
• 28 day cold conditioning @ 48°F
• 28 day bottle conditioning @ ~70°F

The entire batch was highly caramelized (my goal). Beersmith predicted 15 SRM, but the wort was closer to 25-30 SRM. The separate reduction of the first runnings (1.25 gallons boiled down to 1 pint) literally resembled a thick molasses-like syrup by the time I added it back to the main wort.

I aerated with pure oxygen, pitched at 69°F, added a second dose of oxygen 24 hours after pitching, maintained 72°F fermentation temperature for the first three days, heated the fermentation chamber to 74°F for the next couple days, then allowed to drop back to 72°F and maintained there.

Here's my question:

At one week, fermentation activity has ceased entirely and gravity is 1.034 versus target FG of 1.025. Will my FG be higher than predicted (i.e., closer to 1.034 than 1.025) because the caramelization produced a wort that is less fermentable, or should I pitch more yeast (e.g., WLP099 High Gravity Ale) to dry it out?

Note: I am not asking about the effect of boiling off more water and ending up with higher OG. I hit all my targets precisely. I'm asking if my wort is less fermentable because of the chemical reactions in the long boil and separate reduction of the [sweetest] first runnings.

Edit: I realize that I may be using the wrong term -- caramelization vs maillard reaction. What I'm interested in is whether or not my process produced less-fermentable wort.

(Clearly I am trying to avoid being corrected twenty times before I get my first useful answer ;-)

 

[sfgoat]

I think it's more likely that your yeast just hit it's alcohol tolerance and quit.

 

[Calichusetts]

Big beers, small beers...I consistently finish 2 points higher than beersmith suggest when I carmelize the wort. But that's it. Something else is going on.